You will find that this relay is a Phase Sequence Relay, keeping three phase systems running in the correct order.
Instrument Transformers LPVR-480 Phase Voltage Relay Monitor 360-500V 3PH 60Hz
A nice touch is the Miniduino packaging, which keeps parts sorted and reduces the chance of losing tiny screws.
I appreciate black housing for its understated style, which keeps the focus on the wiring and layout.
With 2Pcs included, the size works out nicely for anyone who likes having a backup close by.
A nice touch is the DC 12V operation, as it's easy to wire with basic connectors.
A nice touch is that the HH53P comes with clear markings, making setup less confusing.